Vibracaster - or "How to turn your Valvecaster into a Tremolo"

[kaalaraab]

Howdy!~  My name is Glenn, I often do not say much in the place where there are folks way smarter than I on this, but I have to ask; Are you considering building the GeorgeM2 tremolo shown on page 11? Of "Vibracaster..or how to turn your..into a Tremolo?  Just curious.  I have thought of doing it on perfboard, just like George did, I have all the parts; but I look at the layout, and the pots, installed backwards &upside-down, and lol, I quickly get confused just looking at it!  Anyway, I just wanted to know if you were into this build, and if so how that is going for you.  At some point I will overcome my nerves on it and just go with it!
                                                                         Glenn

That happened to me too. The layout I posted is in the way it should look already printed on the board.

[glenn.b]

Coolness!  That was what I was struggling with-the termination of several components were hard for me to see-that little piece was the missing link!  I'll keep you posted I  NEED to do this!

[kaalaraab]

Ok, this is where I say: "¿Ah, verdad?" First, the led is always on, is that right? I think theres something wrong with the wiring. I hope it is. When I turn the bypass off, I have no sound, so, it is not working. I really hoped this to work at first time 'cause I'm not very good in debugging, but it has to be done.

[kaalaraab]

My LED wired stupid,   

Right:

I find the wiring layout a little bit confusing so I'm tring to sort it out, I really hope that here lies the problem.

[kaalaraab]

  Well, I'm giving up on GeorgeM2 design, I'm very confused with the two switch wiring, I can't figure it out by my self, and this tread seems dead, I'll try the last layout Renegadrian posted. Hope it works at first time 'cause debuggin alone, for me is nearly imposible.

[frequencycentral]

Don't give up. It's probably just a small wiring error. I'll try and get around to having a look over your wiring scheme. 

[kaalaraab]

Ok, I'm not giving up...yet   I'm a little anxious for hear my own vibracaster roaring but, hey, I wouldn't got this far without some patience and your help. So, this is how I wired the 3pdt and the dpdt switches:

3pdt (bypass) switch:





Firs pole: lug 1 --> Pin 2 (through the 47nF capacitor)
              lug 4  --> In tip
              lug 7  --> Jumper to lug 9

Second pole:

lug 2 --> Led and dpdt's lug 6 (firs suspicious connexion)
lug 5 --> dpdt's lug 4
lug 8 --> not connected

Third pole:

lug 3 --> Volume central lug
lug 6 --> Out tip
lug 9 --> jumper to lug 7

Wiring of dpdt switch (tremolo switch):



first pole:

lug 1 --> dept central lug
lug 3 --> diode 4148 -- > pin 8
lug 5 --> In ground and jumper to lug 6

second pole:

lug 2 --> Q3
lug 4 --> 3pdt's lug 5
lug 6 --> 3pdt's lug 2, Out tip, and jumper to lug 5

[kaalaraab]

I just realize that dpdt's lug 6 must go to out ground and not Out tip.

[kaalaraab]

When I cut the wire "3pdt's lug 2" ---> "dpdt's lug 6" The led led turns on and off with the 3pdt switch and responds to oscilation when active it with dpdt switch, but still have no out signal.

[kaalaraab]

I rewired again and can't find the problem, its seems to me there's a short somewhere, or maybe the tube is not working propertly, or still the switches wiring are not right. I'm going, in a few hours, to Guadalajara for Pixie's concert  when I come back I'm going to start over, from the basics: Valvecaster. I'm going to build them all, Valvecaster, Twincaster, Vibracaster without Gain and Volume, etc. because this brings something very clear to me: I have a lot to learn. See you at the weekend.

[kaalaraab]

I built my valvecaster, it was a success. I'm watting for some stuff to arrive and start building a Twincaster. In the meantime I tried again with the vibracaster. This time I used the Adriano's layout on page 5. Nothing Is something with the wiring, Im sure. I just get a bad gronding sound. I'm using BC547c These are my readings:

Q1

E: 0.626
B: 0
C: 5.26

Q2

E: 5.26
B: 8.4
C: 11.87

They are not oscilating at all.

The readings on the pins are:

Pin 1: 3.4
Pin 2: -0.31
Pin 3: 0.05
Pin 4: 0
Pin 5: 11.86
Pin 6: 0
Pin 7: 11.86
PIn 8: 9.56
Pin 9: 5.86

[kaalaraab]

I changed the transistor to see if they were the problem. Voltages are the same except Base of Q2, it droped down to 4.27

[kaalaraab]

Sorry, my mistake, a toke those readings without the tube in the socket, with the tube, the readings are the same.

[kaalaraab]

Third attempt. Failed.  Speed pot does nothing, Depth pot increases and enormous amount of Gain, an enormous amount! Voltages on Q1 and Q2 are in 0 I have soldering issues, I couldn't find strips vero, so I get tripad. I tried to solder everything making jumpers. Now I'll try to relocate components to build it with as few jumpers as possible. I think 4 are going to be enough. Let's do it!

[kaalaraab]

Finally, SUCCESS!! I got my Vibracaster working. I still have the problem with the Depht draining Gain, I'll try with te 220k resistor on the plate. I relocated the components as I said and it worked. I think that what I used is not exactly tripad, here in Mexico City they call it "trama" a column of 4 holes paths between long vertical path lines. Well, the point is it's working. I think is time to try again with GeorgeM2's design.

[kaalaraab]

Suddenly, my vibracaster started to make a real loud noise, hum and his, like if it has ground issues and bad power supply issues. I think the Depht pot is damaged, I'll change it. A quick question, I want my speed to be real fast, how can I do it, will a 100k log pot do the job? Or I'll need to change the resistor value? Currently it is 4.7k.

[frequencycentral]

To increase the speed, reduce the value of one of the 0.47uF caps, it doesn't really matter which one. Alternatively you could do what I did here: http://www.diystompboxes.com/smfforum/index.php?topic=74262.0 Use a switch to alter the 22k (in the Vibracaster). 10k gives faster speeds, 100k give slower. The oscillator is called a phase shift oscillator, and has an inherantly narrow range of speed, hence the switch. Other designs using phase shift oscillators use a dual ganged pot to get a wide range of speeds: http://geofex.com/FX_images/FakeFenderVib3.pdf

[Renegadrian]

I'd like to build the next Vibra with two dpdt switches, one will be on/off with millenium 2 for the led, and the other to switch the tremolo on/off with a dedicated led.
How do I have to wire that second switch!? THX

[frequencycentral]

Adriano, I think the DPDT would select either the tremolo LFO or a resistor to ground. Or maybe just ground.

[Renegadrian]

I guess I have to put the switch just after the diode from the cathode...!?So if it's on it lets the connection to the depth pot.
Is that so?!